Fix bad type annotation to unbreak host-checked mode.

dart/sdk/lib/_internal/compiler/implementation/resolution/members.dart

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 part of resolution;
 
 abstract class TreeElements {
   Element operator[](Node node);
   Selector getSelector(Send send);
   DartType getType(Node node);
@@ skipping 2939 matching lines @@
     inConstContext = node.isConst();
     Node selector = node.send.selector;
     Element e = visit(selector);
     return finishConstructorReference(e, node.send.selector, node);
   }
 
   /// Finishes resolution of a constructor reference and records the
   /// type of the constructed instance on [expression].
   FunctionElement finishConstructorReference(Element e,
                                              Node diagnosticNode,
-                                             Expression expression) {
+                                             Node expression) {
     // Find the unnamed constructor if the reference resolved to a
     // class.
     if (!Elements.isUnresolved(e) && e.isClass()) {
       ClassElement cls = e;
       cls.ensureResolved(compiler);
       if (cls.isInterface() && (cls.defaultClass == null)) {
         // TODO(ahe): Remove this check and error message when we
         // don't have interfaces anymore.
         error(diagnosticNode,
               MessageKind.CANNOT_INSTANTIATE_INTERFACE, [cls.name]);
@@ skipping 62 matching lines @@
       error(node, MessageKind.CANNOT_INSTANTIATE_TYPE_VARIABLE, [name]);
     } else if (!identical(e.kind, ElementKind.CLASS)
         && !identical(e.kind, ElementKind.PREFIX)) {
       error(node, MessageKind.NOT_A_TYPE, [name]);
     }
     return e;
   }
 
   /// Assumed to be called by [resolveRedirectingFactory].
   Element visitReturn(Return node) {
-    Expression expression = node.expression;
+    Node expression = node.expression;
     return finishConstructorReference(visit(expression),
                                       expression, expression);
   }
 }